1. Field of the Invention
This invention relates generally to cable television communication system passive distribution components. More particularly, the invention relates to a signal tap having a housing frame which allows for signal distributing circuitry to be interchanged from either side of the housing frame thereby easily reversing signal direction without disconnection from the CATV coaxial signal cable.
2. Description of the Prior Art
Cable television (CATV) services are provided to customers through a transmission network that typically includes a trunk system transporting a plurality of CATV services from a headend to smaller branches and then onto individual subscriber drops. The transmission medium for the branch and subscriber drops is usually coaxial cable. The transmission network typically includes active and passive components, i.e., line amplifiers, cable taps, cable splitters, and other equipment to distribute the CATV services.
At a subscriber location, the coaxial cable is interrupted with a signal tap which distributes the CATV services to a number of individual subscribers. The signal tap is connected to the coaxial cable using F-connectors and is supported by the cable support strand or a pedestal.
A block diagram of a cable television network 15 is shown in FIG. 1. The coaxial cable 17 functions as a transmission line to provide CATV services 19 to a number of subscribers 21 at various locations. Each subscriber 21 receives signals through the individual taps 23 placed on the coaxial cable 17. Each tap 23 may provide multiple connections.
A prior art signal tap 23 is shown in FIG. 2. The tap 23 includes a body 25, a tap cover 27, a printed circuit board 29 with loss circuitry and asymmetrical connectors 31. The tap cover 27 is provided with a plurality of tap outlets 33, each providing service to a different subscriber 21. The body 25 includes threaded, female F-connector signal input 35 and output 36 ports at opposing ends for connection to the CATV distribution cable 17. The body 25 includes an integral support strand clamp 39 cast in place.
The CATV signal 19 is routed through the printed circuit board 29 rigidly attached to the inside surface of the cover 27 with a plurality of signal tap terminals 41 passing through the cover 27. A pair of signal receptors 43a, 43b are provided on the back of the printed circuit board 29. The printed circuit board 29 distributes the signal received from the headend 19 to subscribers 21 coupled to that tap 23 and passes the signal through to the output connector 36. Since subscriber tap 23 loss circuitry 29 is directional with regard to predetermined frequency bandwidths and the location of the headend, the signal has to enter the input receptor 43a and exit the output receptor 43b in the direction indicated on the tap cover 27. A detailed explanation of the function of the loss circuitry 29 is beyond the scope of the present invention. A metal braid and flexible gasket surrounds the periphery of the tap cover 27 to provide a seal for weather and EMI/RFI ingress.
The tap cover 27 and the printed circuit board 29 are secured to the main body 35 by a plurality of cover bolts at various connection points 45. Upon engagement of the cover, the pair of receptors 43a, 43b engage the connectors 31 thereby completing the circuit and maintaining continuity from the input connector 35 through the printed circuit board 29 distributing the signal to each signal tap 33 and to the output signal port 36 to other downstream subscribers 23.
Periodically, when CATV distribution systems are modernized or rebuilt to higher frequency specifications, the origin of the signal may change necessitating the reversal of the signal connections for each signal tap. As shown in FIG. 3, to reverse frequency direction 50, the coaxial cable connections 47a, 47b on the signal tap 23 must be broken and the tap 23 removed from the support strand 49. The tap 23 must be turned 180 degrees and reconnected to the coaxial cable connections 47a, 47b and support strand 49. By breaking the connections to the coaxial cable 17, potential damage to the connectors 47a, 47b may result.
It is desirable to have a signal tap that easily allows the reversal of signal direction without needing to break the coaxial cable connections.